Dad is dying and abusing pain pills

After my step mom died about 10 years ago my dad moved to Florida (me, my brother, his brother, and sisters are all in Wisconsin) and started dating immediately. He invited his new girlfriends over and they would get drunk and one time one of them passed out in his front yard. He started drinking and thinking it was cool to get drunk, and he still takes as many pain pills as he can get ahold of. I thought that was just a phase but he calls me messed up on pills acting like it's so cool. About 5 years ago I moved to Florida and have recently moved back home to Wisconsin because of jobs but also because I never spent any quality time with him. He always had to make time for his girlfriends and his schedule revolved around them. He's always had low self esteem and wants to impress everyone. He even encouraged me to wear makeup and my contacts instead of glasses when we went to visit his friends at his favorite bars because I was "prettier without glasses." He also blew all his savings on cars and making his house bigger and now he has nothing left. Anyway, last summer he was diagnosed with ALS and decided to stay in Florida because he likes the weather, but i know it's because he wants to be around his girlfriends who break up with him every few weeks. He tries to get me to visit but I'm sick of hanging out with someone who is just bored and messed up on pain pills. His whole family is here. No one wants to sit in Florida with him while he gets drunk and takes pills. Also, I found out I was pregnant a few months ago (have since had a miscarriage) and he told me he was disappointed because I wasn't married and then started talking about a karaoke party he was having and never even asked how I was doing. I've tried telling him I don't want to talk to him when he's on pills but then he'll lie and say he's not on them when he literally just told me he is. He wants me to visit but my time in Florida is done and I hate him. I don't want to waste my vacation time on him. In his defense, he took care of my brother and I when he had visitation (parents divorced when I was born), he was there for birthdays, has helped me out financially during college, and was proud of me when I graduated from college and learned guitar and stuff. Do I ignore him and wait for him to die? Do I write him a letter saying I don't want him in my life anymore? idk what to do.